"I am willing to make a contract with the demon deacon Serlotin, offer my soul as a sacrifice, become a demon, and be ordered by the deacon in exchange for pleasure. If there is any betrayal, I am willing to wash away my sins at the cost of my soul being unable to be freed for generations."
"I am willing to make a contract with the young master Charlotte Phantomhive, dedicate everything I have, and give everything I have, just in exchange for the young master's truly happy smile. If there is betrayal, I am willing to wash away my sins at the cost of my soul being unable to be freed for generations."
If you want to become a devil, start here.
"As the world says, nothing is certain and nothing is impossible. But Serlotin. Maybe it's the same as Charles said. Only you can never abandon me. Never betray me."
"Yes, My lord."